Swift Observations of GRB 200809B

M. Perri (ASDC) for the Swift team

1. Introduction

Sugita et al. (GCN Circ. 28240) reported the GRB detection. The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 15:41:27 UT on 2020 Aug 9. Table 1 contains the best reported positions from Swift.

Table 2 is a summary of GCN Circulars about this GRB from observatories other than Swift.

2. BAT Observations and Analysis

BAT did not observe this burst.

3. XRT Observations and Analysis

Analysis of the initial XRT data was reported by Perri et al. (GCN Circ. 28241).

The light curve (Figure 2) can be modelled with a power-law decay with a decay index of α=1.7 (+2.0, -1.2).

4. UVOT Observations and Analysis

UVOT results are not available.

Figure 1. The BAT light curve is not available.

XRT light curve

Figure 2. The XRT light curve. Any data from a crosshatched region are not included in the fit.

RA (J2000) Dec (J2000) Error Note Reference
01h03m19.09s -73°50'44.1" 4.5" XRT-final UKSSDC
01h03m19.09s -73°50'44.1" 4.5" XRT Perri et al. GCN Circ. 28241

Table 1. Positions from the Swift instruments.

Band Authors GCN Circ. Subject Observatory Notes
Optical Hu et al. 28242 BOOTES-3/YA optical upper limit BOOTES-3 upper limits
Optical Lipunov et al. 28243 Fermi GRB 200809B: Global MASTER-Net
observations report 		MASTER
X-ray Sugita et al. 28240 MAXI/GSC detection MAXI detection
Gamma-ray Fermi 28236 Fermi GBM Final Real-time Localization Fermi GBM
Gamma-ray Gupta et al. 28238 AstroSat CZTI detection CZTI
Gamma-ray Dunwoody et al. 28244 Fermi GBM detection Fermi GBM Epeak=682±246 keV
T90=17 seconds
Fluence=3.717±0.387x10-6erg cm-2
(48th percentile for long GRBs)

Table 2. Summary of GCN Circulars from other observatories sorted by band and then circular number.

August 11, 2020